Process of treating complex sulfid ores.



barren s'ra'ras PATENT @FFICE...

PRQCESS F "mm-nae. COMPLEX SULFED ones..

Specification of Letters Patent.

Patented Oct. 2, 1906.

Application filed February 3, 1906. Serial No. 299,263.

To all whmn it may concern:

Be it known that we, WILLIAM GEORGE.

RUMBoLn and GEORGE PATCHIN, subjects of the King of Great Britain, residing at London, England, have invented a certain new and useful Process for the Treatment of Complex Sulfid Ores After Oxidation and Naturally-Oxidized Ores Containing Zinc, of which the following is a specification.

This invention refers to an improved process for-the extraction of zinc and other metals from complex oxidized ores containin zinc, resulting in the dissolving of the oxide, sulfates, and carbonates .of zinc, nickel, cobalt, manganese, copper, and cadmium from the com lex ores containing these metals, an es-.

sential feature of the process being the treatment of the aforesaid oxidized ores, which have been crushed to a requisite degree of fineness, with a solution consisting of ferric sulfate, sulfuric acid, and sodiumchlorid in water in certain pro ortions and as hereinafterdescribed and c aimed. Heretofore various solvents have been employed for dissolving the metallic substances in such-complex ores. -Thus it has been roposed to crush the ore to be treated, whic ore may or may not be in-an oxidized condition, and:

then to mix the powdered ore with ferric saltsgenerally acid ferric saltsand to treat the mixture electrolytically to produce a solution of metals. It has further been I proposed to subject copper sulfid and oXid to tained being dissolved in the solution of ferrous sulfate produced by thereaction. 'It has also heretofore been pro osed to leach partially or completely oxi 'zed zinc ores first with'a solution of ferrous sulfate and afterward with a solution containing a mixture of ferric and ferrous sulfates and to re.-

' move the zinc from the solution obtained in this way by electrolysis and then to convert the ferrous sulfate into ferric sulfate, and, further, to reduce a portion of this ferric sulfate thus produced to ferrous sulfate by means of sulfurous anhydrid. It has further been proposed toleach roasted zinc ores with a solution of zinc sulfate and ferric sulfate and from the solution thus obtained to recover zinc by electrolysis, producing ferrous sulfate, which by further electrolysis is converted into ferric sulfate.

Now according to the present invention it is essential that the ore'must be in a completely-oxidized condition before treatment, and therefore where the ores are. not naturallyoxidized they are subjected to an oxidizing roasting until the sulfur is removed as far as possible. ally previous to roasting, where such is necessary) to the, requisite degree of fineness to pass a screen having, say, forty meshes to the inch. The crushed and oxidized product is then treated with a solution consisting of ferric sulfate sulfuric acid, and sodium chlorid in water in the proportions hereinafter more particularly stated, whereby all the sulfuricacid radicals in the solvent are used in (itss olving zinc com ounds or other -metallic compounds from the ore without the production of ferrous compounds, and a neutral solution is obtained which is entirely free from salts of iron, and this without the employment of' electrolytic action. The results,

therefore, attained-by this invention are the production of a pure and whitezinc oxid suitable for, aint and'other commercial and 'metallurgica uses from complex sulfid and oxidized ores containing zinc and the recovery alsoas by-products of any cop er, manganese, nickel, or cobalt there may fie in such ores. Moreover, by the removal of the copper, manganese, nickel, cobalt, zinc, and other refractorysubstances it is possible to recover any gold and silver there may be in the ores treated by this process, this recovery being efiectedfrom the ore residues by any of the ordinary methods adopted for the recovery of these metals.

The approximate proportions com osing the solution employed according to this invention, consisting, as aforesaid, of ferric sulfate, sulfuric acid, sodium chlorid, and water, consist of about one per cent. of ferric sulfate, ten parts, by volume, of commercial sulfuric The ore is crushed (gener- .acid,,(or sufiicientchamber acid to equal this strength,) and a small roportion of sodium chlorid, the latter ingre ient varying in quantity according to the composition of the ore to be treated, but in no case being suflicient to dissolve the silver chlorid which may have been formed. These ingredients are dissolved in one hundred parts of water. These proportions are selected with a view to the employment of a relatively small proportion only of ferric sulfate, (which is the main object of the invention,) and this small. propor-.

tion, when mixed, as stated, with a compara tively large proportion, of sulfuric acid, as we do by our invention, is continuously decomposed and regenerated until all the free acid has become neutralized, so that a small pro- 1 5 portion of ferric sulfate is capable of reacting theoretically for an indefinite period, whereby the object of this invention is attained.

The solution, as before described, acts as a solvent upon the crushed oxidized ore, and by this solvent the oxids, sulfates, and car bonates of copper, manganese, nickel, cobalt, and zinc, with other substances, are dissolved and ferric sulfate decomposed. So long as free sulfuric acid remains in the solution the 2 5 ferric sulfate thus decomposed is regenerated and again becomes available for solvent purposes; but when the solvent becomes saturated with dissolved matter from the ore and free from uncombined sulfuric acid the iron is precipitated from the solution chiefly in the form of ferric hydrate, and the solution is then ready to be filtered. The addition of sodium chlorid to the solvent has been found to have a beneficial eflect in making the ex- 5 5 traction of the metallic compounds from the ore more complete, especially when the compounds of copper are found in the. ore. The sodium chlorid, in the presence of sulfuric acid, is converted into sodium sulfate (which is of no value in the process) and hydrochloric acid. The hydrochloric acid so formed acts upon such portions of the metallic compounds as are not readily dissolved by sulfuric acid and ferric-sulfate solution, result- 5 ing in the formation of metallic chlorids, which are decomposed by the free sulfuric acid to form soluble'su-lfates, thus regenerating the hydrochloric acid. It will thus be seen that the beneficial effect of hydrochloric 5'0 acid is under these conditions obtained by the employment of a small proportion only of sodium chlorid, which is only a convenient and economical method of introducing the hydrochloric acid radical. The sodium chlo- 5 5 rid also serves the further purpose of converting any silver sulfate which passes into solution into insoluble silver chlorid, which remains with the ore residues, from which it is subsequently recovered by any of the known methods. The solvent claimed, therefore, is not sulfuric acid, ferric sulfate, and sodium chlorid separately, but the combined and simultaneous action of the three.

The reactions which take place between 5 the solvent and the metallic compounds in the ore' are as follows, which also include some of the .secondary reactions described above:

instance, where sulfuric acid is not conven- 5 iently obtainable the oxidized or roasted ores may be treated with a solvent consisting ofsulfurous acid, sodium chlorid, and waterand this solution is then passed over ore which contains ferric oxid, which it takes up, although it should be understood that with this alternative solution if the ore contains a little or no iron then ferric oxid should be added to the solution. The sulfurous acid contained in this what we have termed alternative solution may, as is-well known, be obtained by absorbing in water the sulfur dioxid contained in the furnace-gases from the roasting of sulfid ores and which can be efiected by allowing these gases to meet a stream of water flowing down an absorption-tower packed with coke or other suitable material, although this mode of obtaining sulfurous acid does not form part of this invention. To the solution thus obtained is added the req- II 5 uisite quantity of sodium chlorid, and it is then passed over the ore, as previously explained, until all free sulfurous acid has been removed to form metallic sulfites. The solution is then permitted to again absorb a further uantity of sulfur dioxid and again is passe over ore, and these operations are repeated until the solution is saturated with dissolved matter from the ore. This sa-tu rated solution is then oxidized by'the action of the atmosphere, or steam or air, or both, are blown through it in order to oxidize the metallic sulfites to sulfates. Further, with our new solvent, whether prepared by the mixture of ferric sulfate, sulfuric acid, sodium 130 Iro cease].

ousol+ zn=znsoi+ct ca SOi+Zn:ZnSO i- Cd, at.

The solution is filtered from the above precipitated matters and treated with an oxidizing agent to oxidize and precipitate the manganese as hydrate. For this purpose we have found the alkaline permanganates, such as potassium and sodium permanganates, most suitable, and when these are employed the manganese in solution, together with that in the permanganate, is precipitated as manganese dioxid or in the form of a hydrate, as represented in the following equation:

The nickel and cobalt are precipitated as the hydrated oxids from the solution by theproper addition of bleaching-powder or some of the other recognized preclpitants for these substances.

2c soi+caciotwcuornango The solution is finallv treated with just sufficient ammonium hy rate to decompose the zinc salts in solution and hydrate oxid of zineis precipitated.

ZnGh-l-QNPLQH Zn(OH)2+ 2(NHQCI.

The hydrated oxi'd of zinc is separated by filtration, washed, dried, ground, and prepared for paint or other commercial and metallurgical uses.

Alternatively, the zinc may be precipitated from the solution of zinc salts obtained by this process by means of barium hydrate or barium sulfid to form a mixed product of either barium sulfate and hydrated oxid of zinc or barium sulfate and zinc sulfid.

znsoi rmornr zn(on) 2+ BaSOi Zn SOi+ BaS ZllSd-BftSOr.

When ammonia is used, this is recovered from the res] dual liquors after the precipitatron of hydrated ()Xlfl of zmc by d1st1llmg these liquors with limeor other oxids of alka line earths.

- unasoaouont ann onmasoi.

The ferric sulfate which is used in the solvent is re eneratedbypassing sulfuric acid and sodium 0 lorid in the proportion of one part, by volume, of acid to ten parts, by volume, of waterover the spent ores, and thus redissolving the precipitated ferric hydrate or other iron compounds precipitated therein, as before described, so that in the continuous use of this process only sufiicient ferric sulfate to form the original solvent is required.

reromwsnzsoi re2(soi)3+crno.

The ore residues from the above operation retain any gold. and silver ori inally present in the ore and may be treate for the recovery of these metals by any of the existing methods.

What we claim as our invention, and de-- sire to secure by Letters Patent, is

1. The process for the extraction of zinc and other metals from complex oxidized ores containing zinc; consisting in passing over successive lots of crushed ore a solution consisting of ferric sulfate, sulfuric acid, sodium chlorid ano water, until such solution bcvcomes saturated with di solved matter, such dissolved matter consisting of the zinc, and also the copper, cadmium, manganese, nickel, cobalt, antimony, lead, bismuth, and tin, or any or all of these metals when contained in said ores, a small proportion'of ferric sulfate being employed in the solution in relation to a large amount of sulfuric acid whereby the ferric sulfate is continuously decomposed and re enerated until all the free acid has become neutralized substantially as set forth.

.2. The process for the extraction of zinc and other metals from complex oxidized ores containing Zinc; consisting in passing over successive lots of crushed ore-a solution conten partsrby volume of commercial sulfuric acid, a small proportion of sodium chlorid-- but not sufficient of the latter to dissolve any silver chlorid which may be formed-and one hundred parts of water, .the ore/being so treated until such solution becomes saturated consisting of the zinc, and also the copper, cadmium, manganese, nickel, cobalt, antimony, lead, bismuth, and tin, or any or all of these metals when contained in said ores, substantially as set forth. 3. The process for the extraction of zinc and other. metals from complex oxidized ores containing zinc; consisting in passing over successive lots of crushed ore a solution containing ferric sulfate, sulfuric acid, sodium sisting of about one per cent. of ferr c sulfate, I

with dissolved mattensuch dissolved matter chlorid and water, until such sb'lution be-- comes saturated with dissolved. matter, then.

treating the saturated solution withmetallic zinc to preci itate the copper, arsenic, antimony, lead, ismuth, cadmium, and tin, sub' stantially as set forth.

4. The process for the extraction of zinc treating the saturated solution with metallic Zinc to precipitate the copper, arsenic, antimony, lead, bismuth, cadmium, and tin, then filtering the solution from the above precipitated matters, and treating the filtered solution with an oxidizing agent, to oxidize and precipitate the manganese as hydrate, substantially asset forth.

, 5. The process for the extraction of-zinc and other metals from complex oxidized ores containing zinc; consisting in passing ,over successive lots of crushed ore a solution containing ferric sulfate, sulfuric acid, sodium chlorid, and Water, until such solution becomes saturated with dissolved matter, then treating the saturated solution with metallic zinc to precipitate the copper, arsenic, antimony, lead, bismuth, cadmium, and tin, then filtering the solution from the aboVeprecipitated matters, and treating the filtered solution with an oxidizing agent, to oxidize and Iprecipitate the manganese as hydrate, then lter out the manganesev hydrate, and then ii d ding bleaching-powder for precipitating'from the solution the nickel and cobalt, substantially as set forth.

6. The process for the extraction of zincand other metals from complex oxidized ores contaming zinc; conslstmg H1 passing over successive lots of crushed ore a solution containing ferric-sulfate, sulfuric acid, sodium chlorid and water, until such solution becomes saturated'with dissolved matter, then treating the saturated solution with metallic zincto precipitate the copper, arsenic, antimony, lead, bismuth, cadmium, andtin, then filtering the solution from the above preeipitated matters, and treating the filtered so tion with an oxidizing agent, to oxidize and precipitate. the manganese as hydrate, then filtering out the manganese hydrate, then adding bleaching-powder for precipitating from the'solution the nickel and cobalt, then filtering out the nickel and cobalt precipitates', then finally treatin the solution wlth 

